KANSAS CITY, MO.—Searchers found a body Wednesday in the rubble of a U.S. restaurant flattened by a natural gas explosion, and authorities said 15 people were injured — two critically.

Kansas City Mayor Sly James did not say whether the person was a man or a woman.

Authorities had been looking for a woman who worked at the restaurant and was reported missing after the Tuesday evening blast. They previously said she was the only person unaccounted for following the explosion and fire.

But James said authorities couldn't be sure that every person who may have been at the restaurant had been accounted for.

“I would always fear there are fatalities in a scene like this,” Kansas City Fire Chief Paul Berardi said earlier Wednesday.

Missouri Gas Energy, the utility that supplies the area, said in a statement that “early indications are that a contractor doing underground work struck a natural gas line.”

Dr. John Verstraete, who works next door to the restaurant, told The Kansas City Star newspaper that several employees of the office smelled gas for several hours Tuesday afternoon. The smell grew stronger through the day, and a gas company employee entered the medical office just before 6 p.m. recommending that it be evacuated, he said.